21145697663 has 2 divisors, whose sum is σ = 21145697664. Its totient is φ = 21145697662.

The previous prime is 21145697659. The next prime is 21145697689. The reversal of 21145697663 is 36679654112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21145697663 - 2² = 21145697659 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21145697653) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10572848831 + 10572848832.

It is an arithmetic number, because the mean of its divisors is an integer number (10572848832).

Almost surely, 2^21145697663 is an apocalyptic number.

21145697663 is a deficient number, since it is larger than the sum of its proper divisors (1).

21145697663 is an equidigital number, since it uses as much as digits as its factorization.

21145697663 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1632960, while the sum is 50.

The spelling of 21145697663 in words is "twenty-one billion, one hundred forty-five million, six hundred ninety-seven thousand, six hundred sixty-three".